soroushrajabnik
New member
- Joined
- Apr 19, 2013
- Location
- Los Angeles, CA
I'm In the process of reviving a 78 242gl that has been sitting on a farm in southern California for a few years. The car only had one owner its entire life and has an amazing chunk of service records and receipts with it. The fuel tank was basically empty thankfully so I put in about 5 gallons of fresh gas, primed the sytem to get some pressure going, and turned on the ignition to see what I could observe. First thing i noticed is that i couldnt hear either fuel pump buzz both when first turning over the key, and also when cranking. Does not Smell like fuel either. I know that the fuel pumps have both been replaced at some point, so im starting to dig into the basics going down the line, Starting with the Fuel delivery bits. The car surprisingly has the original metal volvo branded fuel pump relay made in west Germany with a 1977 manufacturing date so I cracked that open to find some scorching marks and possible shady solder joints so I started with re flowing those joints, and seeing if there was any change. No dice. All fuses are copper and brand new. Upon starting to troubleshoot here is what I have determined:
-With the relay disconnected testing at the harness I have voltage at terminal 30 (red) coming from the battery.
-With the ignition on I do have voltage at terminal 15 as well.
-With the ignition OFF I am reading 385 ohms between terminal 31 (black) and ground..... bad ground here???
-When connecting a tachometer between terminal 31B and ground I am receiving a normal steady 300 rpm signal when cranking. Am also receiving spark at the plugs but thats neither here nor there right now.
-With the relay reconnected and back probing the harness, When cranking I have voltage at terminal 87 (yellow) but NO VOLTAGE at 87B (blue).....
Even while cranking It seems that I am not getting any voltage at the actual fuel pump connections... I know that the NO voltage at 87B is suspect but as far as I know tracing the diagrams this would only affect the CPR and Lambda relay...
Here is where things get a little confusing.
-When I jumper fuse 5 and 7 I get no power at the fuel pumps, and they do not run.... the lights on the dash only come on.
-Now I ran 12v direct to the main pump, and was stumped to find nothing happened until I tapped it a couple times with a rubber mallet and it took off. I tried all the same tests, but jumpering fuses still wouldnt start the pumps.
-When I plug the fuel pump relay back in the harness and actuate the relay manually with the casing off I get power at the pumps and they both run. ALSO when I jumper between terminal 30 (red) and 87 (yellow) on the fuel pump relay harness, I also get power and both pumps run...
I am not an expert when it comes to wiring but I know the basics and I have the right tools. Im also taking these tests directly from between my bentley (fuel injection-CI 240-9) and the original greenbook (CI section 2 group 24) for my diagrams.
I would love some input from some of you who know the wiring on the earlier 240s better than I if anyone has some suggestions...
I am mainly stumped wondering why these pumps dont run when I jumper at the fuse panel, but why they do when I jumper at the harness connections for fuel pump relay... If the bad ground I may have at terminal 31 of the harness is my issue, why will the pumps run when i manually actuate the relay, and also when I jumper at the harness with the relay out???
Help!
-With the relay disconnected testing at the harness I have voltage at terminal 30 (red) coming from the battery.
-With the ignition on I do have voltage at terminal 15 as well.
-With the ignition OFF I am reading 385 ohms between terminal 31 (black) and ground..... bad ground here???
-When connecting a tachometer between terminal 31B and ground I am receiving a normal steady 300 rpm signal when cranking. Am also receiving spark at the plugs but thats neither here nor there right now.
-With the relay reconnected and back probing the harness, When cranking I have voltage at terminal 87 (yellow) but NO VOLTAGE at 87B (blue).....
Even while cranking It seems that I am not getting any voltage at the actual fuel pump connections... I know that the NO voltage at 87B is suspect but as far as I know tracing the diagrams this would only affect the CPR and Lambda relay...
Here is where things get a little confusing.
-When I jumper fuse 5 and 7 I get no power at the fuel pumps, and they do not run.... the lights on the dash only come on.
-Now I ran 12v direct to the main pump, and was stumped to find nothing happened until I tapped it a couple times with a rubber mallet and it took off. I tried all the same tests, but jumpering fuses still wouldnt start the pumps.
-When I plug the fuel pump relay back in the harness and actuate the relay manually with the casing off I get power at the pumps and they both run. ALSO when I jumper between terminal 30 (red) and 87 (yellow) on the fuel pump relay harness, I also get power and both pumps run...
I am not an expert when it comes to wiring but I know the basics and I have the right tools. Im also taking these tests directly from between my bentley (fuel injection-CI 240-9) and the original greenbook (CI section 2 group 24) for my diagrams.
I would love some input from some of you who know the wiring on the earlier 240s better than I if anyone has some suggestions...
I am mainly stumped wondering why these pumps dont run when I jumper at the fuse panel, but why they do when I jumper at the harness connections for fuel pump relay... If the bad ground I may have at terminal 31 of the harness is my issue, why will the pumps run when i manually actuate the relay, and also when I jumper at the harness with the relay out???
Help!